Spawning multiple nodejs threads from single javascript file

I am new to nodejs and javascript. Could anyone advice me on how I can spawn multiple nodejs threads from one javascript file? I will need to pass in the port number while spawning the nodejs threads. Currently, I wrote a batch file to do this.

@echo off

set numberOfThreads= %1 set portNumberToStart = %2 echo step1 %numberOfThreads% :loop if %numberOfThreads%==0 (goto :eof) else (start node . portNumberToStart) set /a numberOfThreads=%numberOfThreads%-1 echo loop %numberOfThreads% goto :loop